Convert object to an array in PHP.

In PHP applications, we often work with data in various formats such as strings, arrays, and objects. Sometimes we need to convert a PHP object to an associative array to process the data more efficiently or to make it compatible with certain functions.

An object is an instance of a class that has properties and methods, while an associative array uses string keys to store key−value pairs. Converting objects to arrays allows easier data manipulation and serialization.

Using json_encode() and json_decode()

The json_encode() function converts a PHP value to JSON string, and json_decode() converts it back to a PHP array when used with the second parameter set to true −

<?php
    class Student {
        public function __construct($firstname, $lastname) {
            $this->firstname = $firstname;
            $this->lastname = $lastname;
        }
    }
    
    $myObj = new Student("Alex", "Stokes");
    echo "Before conversion:
";
    var_dump($myObj);
    
    $myArray = json_decode(json_encode($myObj), true);
    echo "\nAfter conversion:
";
    var_dump($myArray);
?>

Before conversion:
object(Student)#1 (2) {
  ["firstname"]=>
  string(4) "Alex"
  ["lastname"]=>
  string(6) "Stokes"
}

After conversion:
array(2) {
  ["firstname"]=>
  string(4) "Alex"
  ["lastname"]=>
  string(6) "Stokes"
}

Using Typecasting

Typecasting with (array) directly converts an object to an array. This method is faster and more straightforward −

<?php
    class Bag {
        public function __construct($item1, $item2, $item3) {
            $this->item1 = $item1;
            $this->item2 = $item2;
            $this->item3 = $item3;
        }
    }
    
    $myBag = new Bag("Books", "Ball", "Pens");
    echo "Before conversion:
";
    var_dump($myBag);
    
    $myBagArray = (array)$myBag;
    echo "\nAfter conversion:
";
    var_dump($myBagArray);
?>

Before conversion:
object(Bag)#1 (3) {
  ["item1"]=>
  string(5) "Books"
  ["item2"]=>
  string(4) "Ball"
  ["item3"]=>
  string(4) "Pens"
}

After conversion:
array(3) {
  ["item1"]=>
  string(5) "Books"
  ["item2"]=>
  string(4) "Ball"
  ["item3"]=>
  string(4) "Pens"
}

Comparison

Conclusion

Both methods effectively convert objects to arrays. Use typecasting for better performance and when you need all properties, or JSON methods for simple public−only conversions.